Influence of the Cutting Feed Rate on the Hardness and Microstructure of Copper Using Plasma Arc Machining (PAM)

Abstract

This study investigated the influence of the cutting feed rate on the hardness and microstructure of copper machined using a plasma arc (PA) to examine the resulting changes and their impact on the quality of the cut surface. Various constant cutting feed rates and amperage values were used as parameters to measure the cutting performance. Pre- and post-cut hardness measurements and scanning electron microscope (SEM) images were taken. The hardness of the copper surface was the same before and after plasma arc cutting (PAC). PAC did not affect the copper’s hardness or the microstructure of the thermally affected cutting zone. The copper from the cut surface was melted by the PA operation near the edge of the cutting surface with no change in the microstructure. SEM imaging of the cut confirmed this. Thus, the quality of the cutting surface was not affected. In addition, the microstructure of the copper’s thermally affected cutting zone did not alter the cutting surface’s quality. Hardness measurements post-cutting yielded 69.28, 71.65, 70.15, and 60.09 HB for four tests at 500 mm/min and 30 A. The lowest cutting width was 1.504 mm at 12,000 mm/min, and the surface roughness was 2.5 µm at 500 mm/min.